Chapter 10. Type
Conversion

SQL statements can,
intentionally or not, require the mixing of different data types
in the same expression. PostgreSQL has extensive facilities for
evaluating mixed-type expressions.

In many cases a user does not need to understand the details
of the type conversion mechanism. However, implicit conversions
done by PostgreSQL can affect
the results of a query. When necessary, these results can be
tailored by using explicit type conversion.

This chapter introduces the PostgreSQL type conversion mechanisms and
conventions. Refer to the relevant sections in Chapter 8 and Chapter 9 for more information on specific
data types and allowed functions and operators.